On Wed, May 21, 2014 at 2:28 PM, YoungJun Cho yj44.cho@samsung.com wrote:
Hi Daniel
On 05/21/2014 03:01 PM, Daniel Kurtz wrote:
On Wed, May 21, 2014 at 12:42 PM, YoungJun Cho yj44.cho@samsung.com wrote:
There could be the case that the page flip operation isn't finished correctly with some abnormal condition such as panel reset. So this patch replaces wait_event() with wait_event_timeout() to avoid waiting for page flip completion infinitely. And clears exynos_crtc->pending_flip in exynos_drm_crtc_page_flip() when exynos_drm_crtc_mode_set_commit() is failed.
Signed-off-by: YoungJun Cho yj44.cho@samsung.com Acked-by: Inki Dae inki.dae@samsung.com Acked-by: Kyungmin Park kyungmin.park@samsung.com
drivers/gpu/drm/exynos/exynos_drm_crtc.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_crtc.c b/drivers/gpu/drm/exynos/exynos_drm_crtc.c index 95c9435..3bf091d 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_crtc.c +++ b/drivers/gpu/drm/exynos/exynos_drm_crtc.c @@ -69,8 +69,10 @@ static void exynos_drm_crtc_dpms(struct drm_crtc *crtc, int mode)
if (mode > DRM_MODE_DPMS_ON) { /* wait for the completion of page flip. */
wait_event(exynos_crtc->pending_flip_queue,atomic_read(&exynos_crtc->pending_flip)== 0);
if (!wait_event_timeout(exynos_crtc->pending_flip_queue,!atomic_read(&exynos_crtc->pending_flip),HZ/20))atomic_set(&exynos_crtc->pending_flip, 0);I meant that changing this to wait_event_timeout() seems to be masking the original problem, that pending_flip wasn't being cleared.
Yes, I agree.
The original purpose of this patch is to avoid lock-up during modetest (with test_vsync) with command mode panel. In MIPI DSI command mode interface, the display controller can not generate VSYNC signal and uses TE signal instead which is generated by panel. If there is an abnormal power off or reset condition, it is possible that the display controller misses the TE signal and it makes lock-up. So I needed this patch.
If flips are not completing on MIPI DSI, may I recommend that you start a timer when scheduling such a flip in the MIPI DSI driver that will expire after a timeout. In that timer's expiration handler, you can then go through the normal process of completing a flip. This would make the timeout transparent to the generic exynos_drm_crtc layer, which can then do its normal flip complete processing: send pending vblank events, put vblank, clear pending_flip, etc. Does that make sense? Is it possible?
-Dan
Now that you are now clearing pending_flip in the error path, you don't need the timeout, right?
There might be my missing point. Would you explain more detail?
Thank you. Best regards YJ
-Dan
drm_vblank_off(crtc->dev, exynos_crtc->pipe); }@@ -259,6 +261,7 @@ static int exynos_drm_crtc_page_flip(struct drm_crtc *crtc, spin_lock_irq(&dev->event_lock); drm_vblank_put(dev, exynos_crtc->pipe); list_del(&event->base.link);
atomic_set(&exynos_crtc->pending_flip, 0); spin_unlock_irq(&dev->event_lock); goto out;-- 1.7.9.5